Highly tetrahedral, diamond-like amorphous hydrogenated carbon prepared from a plasma beam source

Abstract
A highly tetrahedral, diamond‐like form of hydrogenated amorphous carbon (a‐C:H) with density of 2.9 g cm−3, sp3 fraction of 0.75, and hardness of 61 GPa, the highest values so far attained from a hydrocarbon source gas, has been deposited from acetylene in a novel plasma beam source. The ion energy for highest sp3 fraction is measured to be about 100 eV per C atom, similar to that for a‐C, indicating that the subplantation deposition model of a‐C also describes a‐C:H.